Who wants to read some plugs?!

Looks like you are running rich. Probably need to check your timing. maybe this will help too:

http://www.ngksparkplugs.com/techinfo/spark_plugs/techtips.asp?nav=31000&country=

 

A few points, because I have removed and reinstalled my plugs at least 10 times in the last few months while rejetting carbs. First anti-sieze by Permatex is what I use. Probably any auto parts store- Advanced-parts plus etc. After removing the cap from new plugs with pliers and carefully setting gap .25 for my 79 carb 308. Put a little anti-sieze on finger and roll threads through until you have it all the away around threads. You don't have to use very much and don't have to cover every thread on plug. Screwing them in will spread it around. Careful not to get it on electrode or even bottom of plug.
The rear bank ( toward back of car) is pretty easy and works best with the tool supplied in car tool kit. Probably not many people do this but I am religious about torqueing them in. Torque in to about 11 foot lbs. , unscrew and retorque to about 14 1/2 foot lbs.
Note** It's a good idea to use air to blow out around plug before removing old one, because you don't want crap to fall in hole when you remove plug.
Now the front bank-. Protect roof back edge and edge of hood with tape or towels. Real possiblity of banging them with wrench or plug while screaming curse words. Remove plug wire and then the rubber insert that keeps water from getting in. With good extenders you will probably need pliers to remove extensions as they are awkward to get to. You can get rubber covers for plier jaws at sears hardware so you don't mess up the extenders. I have about 8 "long 3/8" ratchet drive with pivoting head . You will need an approx 3" extension. Buy a good spark plug socket with rubber insert. This is critical. With your hand insert socket extension and plug socket onto old plug in engine. Insert socket wrench in and snap wrench to extension and break loose plug until it spins fairly easily. Unsnap wrench from extension and spin extension with fingers until plug is unscrewed. Here is where rubber plug socket liner comes in. The plug should stay inside socket and be easily removed. When inserting new plugs push new plug into socket and carefully holding socket extension and reinsert carefully into plug hole. You want to do this fairly carefully as the gap will change if you bang the electrode into something on way in. With fingers on socket extension gently screw plug into hole making sure not to cross-thread. Screw in as tightly as possible with fingers. This will assure no cross threading. Then attach torque wrench and fallow instructions for first bank.
The way I do it. I prepare all plugs first.1. Remove cap. 2 set gap. 3 anti-seize and lay out or tray. Only do one plug at a time as less chance of getting junk in engine and mixing up plug wires.

 

As far as the different extenders, different manufacturers make different methods to grab threads on top of plug.

 

Based on the pictures you are running to LEAN. You should have a clean tan/brown look on the tip of the plugs. The problem is there is insufficent fuel flow causing high tip tempatures or the ignition timing is to advanced. When you pull the other 4 plugs it will be interesting to see if they are burning the same. With a twin dizzy set up it could be one dist. is working fine and the other is not. So if you check the timing and it is on for both dizzys then you need a A/F adjustment.

 

definetly lean. the pitting on the electrode insulator is a sign. what grade and brand of gas are you using. the red deposits are mmt fouling. mmt is an anti-knock additive to replace the lead. not a problem in and of itself but it could be indicative of a fuel supply deficiency.

 

I had fouling etc until I:
1. Replaced all the extenders. Mine were the black ones, replaced with black ones.
2. Switched to BPR6's. These are 1 level colder and seem to (counterintutively??) foul less.

If you lost a lot of power all at once, I would suspect that one bank is not getting spark at all. Engine idles nicely but there is nothing there when you try to accelerate. Many causes, e.g. bad coil, bad carbon center in the cap, bad connection to points or electronic ignition, etc.
Get the ignition right before moving to carb adjustments.

Gerrit

 

Aaron,
You look lean to me. The plugs I mean, not you. I would probably pull the idle jets and see what they are (.55? .50?) and confirm that they are clean (soak overnight in carb cleaner, blow dry and inspect). You might need a slightly richer idle jet. Please keep in mind that the idle jets provide the fuel not just for idling, but for the progression hole circuit which is critical to your engine performance under 3000 RPM--i.e. all stop and go driving. These cars were generally jetted a tad lean to pass emissions. Now add 30 years and different fuel formulations and a better flowing exhaust, and you are too lean. (Modern fuels tend to need a little bigger jet than fuels from 30 years ago. I have no idea why, but a very knowledgable carb guy at KTR Motorsports here in MA told me that).

Getting back to your original symptoms (down on power) I would also check that you have no vacuum leaks. They won't cause the plugs to look like that, but a vacuum leak often makes the car run poorly at low RPM. Not many vacuum lines to check on a GT4. Make sure the hose from the vapor recovery tank to the forward intake manifolds is hooked up. Try pulling and plugging that hose just for a comparison. Check to be sure that the brake booster vacuum line is not leaking. (Start the car, rev the engine to get a vacuum, turn it off, then pull the one way valve out of the line that goes up front to the brakes and confirm that you get a "pop" as air enters the line, sounds like uncorking a bottle of Champagne.)

Last year my 308 started doing what you are describing and it turned out the vacuum line from my vapor recovery tank had popped off, so the intake manifold was inhaling fresh air through it. That makes the forward bank go way lean and the car runs badly. It will feel like you are down on power, and you will hear a slightly different sound, like a cylinder isn't firing or something.

If you are able to get the car to rev over 5K RPM, you do not have a bank of cylinders out completely. When you have a whole bank out, such as from a bad coil or points, you will have a VERY limited amount of rev power and the thing will stink of gas because one whole bank is dumping raw fuel into the exhaust. Obviously, if that happens, shut the car off QUICKLY no matter where you are. If you persist in driving under those conditions, the car WILL catch on fire.

I agree with Gerrit that you should check the ignition before messing with jetting. Replace the extenders. They have a limited lifespan, and check the timing.

Birdman

 

It is hard to tell from the pictures - is the pitting on the first plug picture a coating on the insulator that has flaked off or is it actually the insulator that is breaking down? I was assuming it was a coating that was flaking off and was relatively harmless.

Also double check that the ground electrode is in good shape on that plug. It looks a little like it has a crack at the base, but that could just be a line in the crud that has gathered. I hadn't noticed that before for some reason.

 

Begging to differ, what I've always heard is fuel mixture is read on the inside of the steel housing(threaded piece). Plug heat range or temp is read on the porcelain part of the center electrode. Keep in mind I'm wrong every day.

 

IMHO,

The first plug is definately running too hot.

It could be: a) a lean mixture, b) advanced timing, or (not likely but...) c) it could be that the plug is too hot.

I'm assuming for the moment that the 5's are the right plug. I have 7's in mine, and here's what they look like.

(sorry for the picture quality. I really need to get a decent digtal camera.)

They're all as black as the photo indicates. Wet fouled. Black, with black carbon deposits on the electrodes.

Mine are too cold. The 7's are colder plugs than the 5's, as they have a smaller ceramic insulator, which allows the heat to pass more quickly through the body of the plug, to the block.

But, I may also be running a little rich. But I'll find that out later, after I change my idle jets too. I just learned I have 55's.

But at least I'm not hot. Although I may be running rich. But it's hard to tell at this point. Because I'm certain that the plugs are too cold anyway. I remember reading somewhere else here, that NGK BP5ES are the correct plugs. Although the book calls for, Champion N7Y or Bosch W 200 T 30.

Interesting to note however, the difference in the body's of the plugs from the front row, to the back row of plugs. Guess which ones were in the rear (easiest to get to) bank?

The previous owner said he had a full tune-up, service, and carb adjustment before I came to get it. Luckily that specialty tune-up service won't be touching "this" car again!
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If you took a poll here of what plugs people are using on carbed 308s with the points ignition, you will likely find that most people are using NGK BP5ES (or similar heat range in another brand). The hotter plugs seems to resist fouling a little better.

Birdman

 

It looks like someone ran too much aftermarket octane boost in teh gas tank. have you ever put in octane boost? that tends to turn the insulator reddish.

 

I just changed my plugs this weekend and they were the stock NGK BP7ES reading very rich. I just switched to the NGK BP6ES...one heat range hotter.

 

To quote that great mechanic from Passaic, Butch Bohunk: "Always make sure yer %$@#* sparks are in order before you go screwin' around with the damn carburation!"

I would: 1) first check timing on both banks, 2) once that is verified as correct, then and only then move on to checking jet sizes and carb adjustment, 3) check/change your fuel filter, 4) check for vacum leaks as wisely stated previously, 5) consider replacing plug wires/extenders if you think they are questionable.

The symptom happening only when hot also raises the possibility of fuel boiling before it gets to the engine. I know this is fairly common on British cars which have an external float bowl on their S.U. carbs, especially if the heat shielding is removed, as some well-meaning englishman wisely located the carbs about 2 inches above the exhaust header. The end result when idling in hot weather is that the fuel sitting in the bowl gets too hot and vaporizes, which results in poor running similar to what you are describing. Don't get me started on what happens when you have a LEAKY carb sitting directly above a hot exhaust header.... Anyhow, I suppose the end result of this fuel vaporization is a lean ruinning engine since it is getting insufficient fuel. Maybe this could be a component to your problems? I am not terribly familiar with webers, and I do not know if similar fuel vaporization problems can be an issue on Ferraris. Anyone know?

Remember that there is always a decent chance you have more than one problem occuring at the same time, i.e. your timing may be off AND your plug extender is crapping out on you. And remember that it is impossible to correctly adjust carbs if the timing is not first set to spec. You will only be covering up a timing problem by adjusting the carbs further out of whack. A good running engine always starts with the ignition. Good luck and hope you get her purring again soon!

 

That was good advice given and need repeating. Make sure ignition timing and components are spot on before screwing around with the carbs.

BTW, you can do the plug diagnostics (1st pic) but not plug reading (perfect color on porcelain and tip, etc). The reason is the gasolines of today don't allow you to do anything other than plug diagnostics (overheated porcelain, oil coated, etc.) These boutique fuels with oxygenates, additives and no lead will not read like the gasolines of old.

Once you get the ignition sorted and the plugs looking the same, find find someone with a dyno and an exhaust gas analyzer to check the carbs.

 

I know that it happens with S.U. carbs that have external float bowls full of gas. I have never worked with Webers, but I don't think they have a float bowl. That is not to say that fuel could not be vaporizing somewhere else in the carb itself or in a fuel line. I would check to make sure that all your fuel lines are located properly and not touching anything hot that they are not supposed to. I don't know what heat shielding is supposed to be present on a GT4, but I would make sure it is all as it should be and you aren't missing anything.

 

Aaron,

You have a Ferrari, not a Triumph or MG. You carburetors are on top of the engine, away from the exhaust headers. So that is not your problem.

You "may" be running lean. But it's impossible to tell rich from lean right away, simply by looking at the plugs for the first time.

This is something that has to be done progressively, over time to determine what's going on.

So, check the timing first.

Then check for vacuum leaks, because extra (unwanted) air coming in will lean the mixture.

A vacuum leak is not a mixture problem that can be fixed properly with re-jetting or by adjusting the mixture to compensate for it.

Put some new plugs in, and drive it for awhile to see how it performs. If the performance is very similar, or the same: Then, pull the plugs again and examine them. If they're not tan (self cleaning) colored, but are still looking like a lean mixture; Then (and only then) look at correcting it by adjusting the carbs.

And keep checking them. When they've become oil fouled like mine, then you're too rich. In which case you can lean it a little until they self clean. Then you should be just about perfect.

I'm no expert, but I had to learn to use this basic technique to keep my Alfa mixture in line, so I don't blow out expensive catalytic converters.

 

i posted a few times about there bieng very noticable differences in the plug holes in the cam covers. my 78 GTS = no issues. my 77 GTB front bank plug holes were smaller, but not impossible 74 308gt4 = the freaking plugs were impossible to remove from the front bank, even with the ferrari tool. i had to take a socket to the machine shop at work and have it turned down to fit. i still have the socket and i only use it when i have to as i am afraid it will crack.

its been my experience that BP5ES NGK plugs are too hot , even with 60 s and 135s. assuming everything else is correct and serviceable, all three of my 308s got BP6ES NGK plugs, QV extenders, 55 idles and 135 mains. F36 e-tube and i was playing with the air corrector jets between 190 and 220 depending on what time of year it was. i would not run BP5s espesially if you have 55 idles and are running lean my GTB actually ran hotter water and oil temps with the BP5s when driven hard, so i went back to bp6s.


best.


Michael





ps I NEED ANOTHER CARB CAR .......